#include <stdio.h>

int main()
{
    int n = printf("Hello world!");
    printf("\n%d\n",n);
    return 0;
}

/*
int main()
{
    int id = 0;
    float Chinses = 0.0f;
    float Math = 0.0f;
    float English = 0.0f;

    //输入
    scanf("%d;%f,%f,%f",&id,&Chinses,&Math,&English);

    //输出
    printf("The each subject score of NO. %d is %.2f, %.2f, %.2f.\n",id, Chinses, Math, English);

    return 0;
}
*/